The field of the invention is numerically controlled machine tools, and more particularly, the development of part programs for numerical control systems on such machine tools.
Numerical control systems direct machine tools such as milling and drilling machines through a series of moves to machine a part. The desired series of moves form a part program which is input to the numerical control system. Such part programs may be stored on a magnetic or punched tape or they may be coupled through a communication link from a host computer in a DNC system. The format and coding of part programs for use on commercially available numerical control systems is standardized and thus as a practical matter a machine for developing such a part program must generate its work product in one of the standard forms.
Prior systems for generating part programs are expensive, time consuming and require the skills of a trained computer programmer. Such systems employ high level languages such as APT or UNIAPT to define the part which is to be machined. The operator must be skilled in the use of the language in order to formulate the statements which properly define the geometry. Following this, the developed program must be pre-processed and then post processed to convert the statements into a standard part program format and code. Such processing usually requires the use of a large general purpose digital computer which is expensive and which may involve considerable time. If an error is made, or if changes in the program are desired, the entire process usually must be repeated.
Prior systems for generating part programs are particularly impractical for small machine shops which cannot justify the cost of a general purpose digital computer or the hiring of a skilled programmer. As a result, the use of numerically controlled machine tools at such establishments has been limited. Also, even when the equipment and skilled programmer are present, the cost and time required to generate a part program may more than offset the advantages of making the part on a numerically controlled machine. This is often the case when only a few of the same part are to be made, in which case it is more practical to employ a manually operated machine.